Étude de la conversion thermoélectrique indirecte : application aux amplificateurs de puissance

Abstract

Thermal management of telematic electronic components is a major concern. Some systems such as power amplifiers (PA) have fairly large heat losses which affect the proper functioning of the circuits and weigh on the energy bill. Therefore, ensuring the cooling of the circuits and providing energy-efficient solutions is essential. The objective of this thesis is to design an eco-responsible structure allowing PA-heat recovery while maintaining an adequate operating temperature. Our system tends to transform the dissipated power of PA into electricity based on the properties of piezoelectric materials. To do this, we design a geometry suitable for low power levels applications. It produces a thermomechanical energy conversion necessary to stress the piezoelectric material. Then, we develop an analytical model of the structure. We implement this model on Matlab to size the system based on a preliminary material study, and to simulate the response of the piezoelectric generator. Once our recuperator is fully defined, we perform a multiphysics simulation with COMSOL Multiphysic. This simulation verifies the robustness of the analytical model and models the interactions between thermal, mechanical and piezoelectric phenomena, precisely. Given the agreements between the two simulation methods, we build an experimental prototype and analyze the measured results. The designed generator is an innovative structure for heat recovery. It uses a piezoelectric material in the coupled mode 33, little studied in literature. Besides, it is suitable for low-power operation. The system response is promising. The theoretical efficiency is of 4.48% for a dissipated power of 3W. Moreover, the structure ensures the circuit’s cooling by maintaining the temperature level at approximately 45°C. Furthermore, experimental measurements reproduce the appearance of the simulated response.

Date	20 May 2020
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Ammar B. Kouki (Supervisor)